The invention relates to a tool, especially for producing cores, which is arranged in a casting system and wherein the tool comprises first casting half shells and second casting half shells.
Such tools are used, for example, in the so-called xe2x80x9clost core technique,xe2x80x9d in which cores of a low-melting metal alloy are cast in the low-pressure process in a multi-part mold. These cores are then placed in a plastic injection molding machine. The plastic part is produced by injecting synthetic resin material around the core into the injection molding die. After the synthetic resin enclosed core has cooled, the core is melted out by applying appropriate fusion heat. For this purpose the plastic part with its enclosed core is immersed in a heated bath and by inductive support a uniform fusion of the core is achieved. The core is produced in a horizontally arranged casting system. Since the core has a relatively large mass, a long cooling phase is necessary. This means that the cycle times are substantially influenced by the cooling times and under some circumstances they are substantially longer than the subsequent cycle times when thermoplastic synthetic resin is injected around the core.
Consequently, until now it has been necessary to have several core casting machines to make it possible to produce a certain number of cores within a certain period of time.
It is the object of the invention to provide a a tool, especially for the production of cores, which enables shorter cycle times to be achieved.
This and other objects have been achieved in accordance with the present invention by providing a tool which comprises first casting half-shells and second casting half-shells, with two planes of separation or parting planes being provided and two casting units having first and second casting half-shells being formed, in which the parting planes are situated one behind the other in the direction of movement of the two casting units.
A significant advantage of this invention is that at least two cores can simultaneously be cast in parallel in a single core casting machine, and thus the cycling time can be halved.
In one embodiment of the invention it is proposed to couple the casting half shells, which move parallel to one another, together by means of connecting rods. The application of force thus is effected through these connecting rods, and optionally a packet of springs can be provided to compensate for tolerances.
In accordance with another embodiment of the invention, each half shell is equipped with one or more ejectors. The core casting machine can be provided with a plurality of casting units arranged side by side. Thus, for example, four or six cores can be produced in a single working cycle.
To enable the cores to be removed by a gripper, in another embodiment of the invention the tool is moved after the casting operation such that the cores on both sides are released and can be removed.
These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be implemented in embodiments of the invention either individually or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed.